This week's Time magazine cover has reignited a parenting debate just before Mother's Day: How old is too old for breastfeeding kids?

Time shows 26-year-old married mom Jamie Lynne Grumet on the cover with her 3-year-old son sucking on her breast while standing on a stool. The boy, Aram, turns 4 next month. The extended nursing period is part of a phenomenon known as "attachment parenting."

While less than 25 percent of U.S. women are still breastfeeding after a child's first birthday, attachment parenting is where kids are breast-fed for an extended period of time. The behavior is based on Dr. Bill Sears' "The Baby Book," published in 1992, which encourages parents to nurse longer, attach infants with a sling (known as "baby wearing") and co-sleep with their children through development years.

Most readers reacted with surprise and shock, but some agreed with Grumet's attachment parenting.

"It gives me the creeps, too," laylaloo added. "I breastfed my child until 10 months of age; I know some moms who continued breastfeeding into the second year, but all stopped long before the kid turned 3."

"I think it's great," piperatdawn wrote. "My wife breastfed our child past age 3 and she is well adjusted and healthy. We are not helicopter parents. Breastfeeding well into toddlerhood is completely normal biologically and is still practiced in many cultures. There is nothing offensive about feeding a child and it's not sexual. If someone feels good breastfeeding it's because there are hormones released that promote relaxation and bonding. 'Sick' and 'abnormal' are in the eye of the beholder. It reflects poorly on the people who make those comments, not the women feeding their kids in a completely natural and normal way."

"I feel bad for the woman that is going to marry this kid," virge11 said of the toddler. "Talk about a momma's boy."

AhlCrunch commented: "Big deal! Breasts are seen as a sex object when it is quite clear they are for another purpose such as what the cover depicts. This has been going on since our primate ancestors, prehistoric ancestors and even 200,000 years ago when modern man first appeared."

L.A. Weekly reports Grumet, who lives in Los Angeles, has long been advocating the lengthy breastfeeding period and was breastfed herself until she was 6 by her mother. Grumet's parenting blog has crashed from traffic since Thursday, but photos she submitted for another mommy blog show her nursing 3-year-old Aram and her adopted 5-year-old son -- both at the same time.

Grumet also defended her parenting habits on NBC's "Today" show Friday: